Prefolded diaper with improved leg fit

ABSTRACT

A prefolded disposable diaper of the wing fold style and having a transverse fold in which each of the side edges adjacent the transverse fold are fastened securely to each other a predetermined distance from the transverse fold whereby the length of each of the side edges is made effectively shorter than the normal full length dimension of the diaper. These shortened side edges provide a closer fit around the child&#39;&#39;s leg at the interior thigh area. A downwardly depending fin formed at the side edges by the edge securement also defines a side pocket on each side useful as an additional entrapment area for excrement.

United States Patent [191 Endres [4 1 Nov. 19, 1974 PREFOLDED DIAPERWITH IMPROVED 3,744,494 7/1973 Marsan 128/287 Primary Examiner-AldrichF. Medbery Attorney, Agent, or Firm-Daniel .1. Hanlon, Jr.;

William D. Herrick; Raymond J. Miller [5 7] ABSTRACT A prefoldeddisposable diaper of the wing fold style and having a transverse fold inwhich each of the side edges adjacent the transverse fold are fastenedsecurely to each other a predetermined distance from the transverse foldwhereby the length of each of the side edges is made effectively shorterthan the normal full length dimension of the diaper. These shortenedside edges provide a closer fit around the childs leg at the interiorthigh area. A downwardly depending fin formed at the side edges by theedge securement also defines a side pocket on each side useful as anadditional entrapment area for excrement.

,5 Claims, 7 Drawing Figures /|NWARD FOLD LINE OUTWARD FOLD LINE PATENIHQV 1 9M4 I SHEET 10F 2 /INWARD FOLD LINE OUTWARD FOLD LINE FIG. 3

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FIG.

PREFOLDED DIAPER WITH IMPROVED LEG FIT BACKGROUND OF THE INVENTION Inthe art of disposable diapers it is known that by prefolding rectangulardiapers in a suitable manner it is possible to provide a somewhat betterleg fit at the inner thigh which tends thereby to minimize leakage ofboth fluid and solid excrement. However, there is a need for stillfurther improvements in leakage control. This invention is directed toone such improvement.

An example of one commercial form of prefolded disposable diaper towhich the improved structure of this invention can be applied may befound in U.S. Pat. No. 3,196,874 to Hrubecky and assigned to theassignee of this invention. The diaper described in that patent, hasinward and outward diagonal folds on each side of a central pocket atthe medial transverse fold line which form leg receiving areas on eachside of the diaper. This style of fold will be referred to hereinafteras a triangular wing fold.

Another example of a commercial form of prefolded diaper to which theimproved structure of this invention can be applied may be found in U.S.Pat. No. 3,180,335, to Duncan, et al. The prefolded diaper described inthat patent has inward and outward folds extending longitudinally forthe full length of the diaper on each side of an elongate central panelsection. The longitudinally folded diaper is also folded transversely inhalf. This style of fold will be referred to hereinafter as alongitudinal wing fold. It should be noted that this patent is citedonly to illustrate the style of fold rather than its other distinctiveaspects.

Both the longitudinal and wing fold diaper described in the abovepatents also suggest adhesive securement of facing surfaces of theprefolded diaper which securement is located a substantial distanceinwardly of the diaper side edges to assist in retaining the folds atleast until such time as the diaper is attached to the infant.

In studying the. causes of diaper leakage at the thighs it was notedthat for both the triangular and longitudinal wing fold diapers a fairlysnug fit is obtained initially when either style diaper is first appliedto the infant. However, the fit appears to become progressively lesssnug the longer the diaper is worn.

With the improved structure defined herein a tighter initial fit at thethighs appears to be obtained which is retained for the entire time thediaper is worn to aid in reducing the number of leakage incidents.

SUMMARY OF THE INVENTION The invention is directed to an improvement inprefolded rectangular disposable diapers of the wing fold type. The foldmay be either the triangular or longitudinal style of wing fold. Theimprovement comprises permanently securing together the side edges ofthe prefolded diaper at a predetermined distance from the transversefold line of the diaper. This securement foreshortens the diaper sides,and the shorter sides permit the diaper to be fastened more snuglyaround the legs. Securing together the sides in this manner also forms aprotruding external fin at the transverse fold line on each side of thediaper, as well as a small inwardly dis posed pocket on each sideadjacent each of the secured portions. The fins also serve to keep thediaper from being flattened when it is initially spread open forapplication to the infant. The side pocketsprovide additional catchmentsfor body discharges. It has also been found that when the diaper isapplied to an infant, the shortening of the diaper sides in the mannerdescribed holds the central portion of the diaper further away from thedischarge orifices of the infant than a diaper without such structure.It is believed that this greater distance exposes a larger target areaof the absorbent surface in the center of the diaper pad to the initialimpact of urine and fecal discharges and thereby reduces the chances forrun-off. In addition, the shortening of the diaper side edges provides astructure with a deeper pouch between the legs and appears to improvetotal capacity.

The above features and other advantages of the invention will becomeapparent by the following detailed description and accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a diagrammatic plan view of the surface of a rectangulardiaper schematically illustrating the fold lines and a means for edgesecurement of one form of a triangular wing fold diaper embodying theinvention.

FIG. 1A is a fragmentary plan view of a part of a diaper similar to FIG.1, but showing another embodiment of the invention.

FIG. 2 is a perspective view of the FIG. 1 diaper illustrating theinitial direction of fold taken by various parts of the diaper as it isbeing folded.

FIG. 3 is a perspective view of the FIG. 1 diaper with the folds almostcompleted.

FIG. 4 is a diagrammatic plan view similar to FIG. 1 but illustratingthe fold lines and a means for edge securement of one form of alongitudinal wing fold diaper embodying the invention.

FIG. 5 is a perspective view of the FIG. 4 diaper illustrating thedirection various parts of the diaper initially move as it is beingfolded.

FIG. 6 is a perspective view of the FIG. 4 diaper with the folds almostcompleted.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Turning now to thedrawings, FIG. 1 is a plan view of a rectangular diaper schematicallyillustrating one form of the line pattern on which a triangular wingfold diaper may be folded. As will be noted, this diaper has atransverse fold line 12 dividing the diaper into approximate halfsections; a pair of diagonal fold lines 14 extending from theapproximate center of the diaper on each side of transverse line 12 tothe respective edges of the diaper short of the diaper ends; and anotherpair of diagonal fold lines 16 extending from points on the transverseline 12 midway between the center and edges thereof to the same terminalpoints on the diaper edges as lines 14.

When folding the diaper to its marketed configura tion, the diaper isfolded inwardly on lines 14 and outwardly on lines 16 as partially shownin FIG. 2 to provide the folded configuration shown in FIG. 3, which isin its almost completed form.

While the FIG. 3 configuration is shown as partly opened it will beunderstood that the diaper in its final folded form will be collapsedwith the surfaces of all folded sections in contact. It will also be'understood that while, as shown in these drawings, lines 14 diverge tothe outside edges from the approximate center of transverse line 12,lines 14 can also diverge from points spaced from the center and locatedbetween the center of line 12 and the diaper edges. The transverse foldline 12 need not divide the diaper into exactly equal halves, since itmay be desirable for the waist portion to be higher or lower in front.

The improvement of this invention comprises shortening the diaper edgesto a length dimension which is significantly shorter than the overalllength of the diaper by securely fastening selected portions of thediaper side edges to each other adjacent the transverse medial foldline. The shortened area of the diaper edges, for example, may be thatpart of the diaper edge enclosed in brackets 18. When thisforeshortening is done, for example, by utilizing an adhesive line atthe diaper edges, which adhesive line extends an equal distance on eachside of transverse line 12, portions of the folded diaper edges aresubstantially permanently secured to each other in a manner to form adepending fin 22 at each edge of the diaper at transverse line 12. Thefin 22 normally extends inwardly from the edge at least to fold line 16,where it may blend into the transverse fold line. In the embodimentillustrated, adhesive 20 also seals that portion of the side edges ofthe diaper which comprise each of the fins 22.

While this edge securement is shown as an adhesive line 20, otherfastening means such as stapling, sewing or taping may be used. When aline of adhesive is used it may also be applied on only one side of line14, rather than both sides as shown, as long as a secure joining of theedge is obtained. The securement areas may also comprise a spot jointspaced from line 14 rather than a continuous edge seal, but this is aless favored method of securement.

The edge securement, as described, serves several purposes:

First, it permanently shortens the dimension of the diaper edges to makethe edge dimension significantly less than the overall length of thediaper.

Second, it provides a small functional pocket portion 24 at each side ofthe diaper on the transverse line 12 and adjacent each edge, whichpocket serves as a supplementary excrement trap.

Third, by preventing the central bottom portion of the diaper along thetransverse line from being drawn closely against the infant's body whenworn, it allows that central portion of the diaper to hang lower andfarther away from the infant when in place, thus in effect providing abigger pouch for the reception, and mechanical holding therein, of bodyexcretions without increasing the size of the diaper. With thisstructure, the functional absorption ability of the absorbent coreelement also appears to be increased. While the reason for the latter isnot known, it is believed to be due, among other reasons, to thepossibility that the lower hanging pouch exposes a larger target areafor the body excretions to strike as they are discharged, as well asassisting retention by gravity.

Fourth, by shortening the edges the diaper is provided with a tighterleg fit in the thigh area when the diaper is in place on the infant.This tighter fit appears to remain effective for a longer time whencompared to results for similarly folded diapers without the shortenededges.

FIGS. 4-6 illustrate another embodiment of the improvement of thisinvention as applied to a longitudinal wing fold diaper.

The plan view of FIG. 4 illustrates a pair of inward fold lines 34,transversely spaced from the center of the diaper and extendinglongitudinally for the length of the diaper on each side of transversecenter line 28, and a pair of outward fold lines 36 disposedintermediate lines 34 and the diaper edges. These longitudinal foldlines divide the diaper into a large central panel flanked by twosubstantially equal narrower panels on each side. The direction in whichthe panels are longitudinally folded at the start of the foldingoperation is shown in FIG. 5. The longitudinally folded diaper is alsofolded transversely on line 28. The almost completed fold is shown inFIG. 6.

In this longitudinal wing fold embodiment, as in the embodiments of thetriangular wing fold shown in FIGS. 1-3, the improvement comprisessignificantly shortening the length of the diaper edges by fastening theedges securely adjacent the transverse fold. In this illustration, theshortened portion comprises the edge length enclosed within brackets 38.As further illustrated in this embodiment, such shortening is obtainedby utilizing an adhesive strip 40 extending the same distance on eachside of transverse line 28. Thus, when the diaper is in its finaltransversely folded configuration, these adhesive lines are joined toform a permanent fin 44 on each edge of the diaper at the transversefold line.

Securement of the diaper edges in this way, or by using other fasteningmeans, provided the longitudinal wing fold diaper shown in FIGS. 4-6with advantages similar to those set forth and described for the FIGS.1- 3 triangular wing fold diaper.

The depth of the external fins 14 in the triangular wing fold diaper andexternal fins 44 in the longitudinal wing fold diaper may vary and stillpermit the fins to perform their improved function. From a performancestandpoint an optimum fin depth has been established for each of thediaper sizes now marketed.

For example, a newborn size diaper is about 10 inches X 14 inches andthe preferred depth of the fin for this size is inch, or an overall edgeshortening of l-%inches.

A medium size diaper is about ll inches X 16 inches and the preferreddepth of the fin is inch, or an overall edge shortening of 1- /2 inches.

A toddler size diaper is about 12- 16 inches X 17-% inches and thepreferred depth of the fin is 1 inch or an overall edge shortening of 2inches.

A suitable depth of the fin may also be characterized as a percentage ofthe overall diaper length. Improved functions are obtained if the depthof the fin comprises from about 4 percent to about 7 percent of theoverall diaper length, or stated another way, if the amount the diaperedges are shortened is from about 8 percent to about 14 percent of theoverall diaper length, i.e., twice the fin depth. In general, thesmaller size diaper desirably has a fin depth nearer the lowerpercentage range while the larger size diaper has a fin depth nearer thehigher percentage range.

It is understood that this invention is particularly applicable towing-folded disposable diapers of the type which generally comprise anabsorbent core of fluffed wood pulp fibers or absorbent wadding and thelike, a pervious top sheet, and an impervious backing sheet.

Many variations of such disposable diaper structures are now beingmarketed by several manufacturers. The invention applies to all suchdiaper variations as long as about 28 grams; medium diapers 29 grams,and toddler diapers 29 grams.

Results were as follows:

Urine Leakage it is feasibleto shorten the edges and provide the finstructure as described above.

While in each instance, the diaper is shown as being fastened by a lineof adhesive adjacent and parallel to each edge at the transverse foldline, it is understood that other permanent securement means may be usedsuch as sewing, stapling, taping or the like. The important requirementis that the attachment be sufficiently? strong to maintain the shortenededge dimension in use.

The entire side edge of the fin need not be sealed in the manner whichresults when one uses an adhesive line parallel to the edge as shown inFIG. 1, although this is the preferred structure. Another way of sealingthe diaper, for example, is by using a spot joining at the edge whichspot is spaced from the transverse line; or as shown in the fragmentaryplan view of FIG. 1A by a diagonal line or lines of adhesive 20a. Asshown here, the line or lines extend diagonally from the edge of thediaper to the intersection of lines 12 and 16.

- The following specific examples illustrate the effectiveness of theshortened edge structure in improving retainment of excretions andreducing leakage.

The diapers tested 't'i'i''rfi'n from coin riie rcial lots of KlMBlESdisposable diapers. Comparisons were made between modified andunmodified newborn, medium, and toddler size diapers. These diapers areman-- ufactured substantially in accordance with the aforementionedl-lrubecky U.S. Pat. No. 3,196,874 and are generally characterizedherein as triangular wing fold Each of the diapers have an absorbentcore of airformed wood fluff fiber, wrapped in an absorbent crepedtissue sheet, a fluid pervious cover sheet of scrim reinforced absorbenttissue, and a backing sheet of 1.0 mil embossed and white pigmentedpolyethylene. A pair of pressure sensitive adhesive tapes are attachednear one end of the polyethylene backing for use in maintaining thediapers in place around the infants waist.

1n the following tables the unmodified diapers of each size areidentified as regular diapers, and the modified diapers are identifiedas having a fin of specified depth. The newborn diapers were tested oninfants of less than about 14 lbs. in weight, the medium on infantsweighing about 12-22 lbs., and the toddlers on infants weighing overabout 20 lbs. The newborn diapers tested had an average fluff and tissuewrap weight of Urine leakage is a subjective trait measured byvisiiai""""""" .and/or tactile observations of the mothers, based on,their identification of wet or damp garments or bed clothing. Topleakage refers to leakage at the waist.

jonly those diapers which contained feces, the number ;of which was muchlower than the total sample size in each case.

It should be noted here that both the l-lrubecky U.S.

Fat. No. 3,196,874 and the D'u'fiii, et al., U.S. Fat

No. 3,180,335 mentioned earlier teach among other features the use ofadhesive spots to retain their multifolded structure until the diapersare applied to the infant. However, it is clear that neither thepositioning of these adhesive spots nor their disclosed function operateto permanently shorten the side edges of the diaper as disclosed herein.Accordingly, the manner of ad hesive fastening of interior contactingfaces of the folded diapers as set forth in these two referenced patentsdo not obtain the improved efficiency of the structure set forth in thepresent invention.

What is claimed is:

1. In a disposable prefolded rectangular diaper of the wing fold typehaving top and side edges in which side portions of the diaper are firstfolded inwardly, in which marginal portions are then folded outwardly,and in which the diaper is further folded approximately in half in thetransverse direction; the improvement wherein the facing surfaces of thefolded diaper are securely fastened together at each of the side edgesin an area closely adjacent the transverse fold in a manner to shorteneach of said side edges to prevent extension of the side edges to fulllength and to provide downwardly extending fin portions adjacent thetransverse fold of each of said side edges, which fin portions areretained when the prefolded diaper is opened up and applied to Notice ofAdverse Decision in Interference In Interference No. 99,193, involvingPatent No. 3,848,595, D. D. Endres, PREFOLDED DIAPER WITH IMPROVED LEGFIT, final judgment adverse to the patentee was rendered Nov. 17, 1977,as to claims 1, 3, 4 and 5.

[Ofiicz'al Gazette February 14, 1.978.]

1. In a disposable prefolded rectangular diaper of the wing fold typehaving top and side edges in which side portions of the diaper are firstfolded inwardly, in which marginal portions are then folded outwardly,and in which the diaper is further folded approximately in half in thetransverse direction; the improvement wherein the facing surfaces of thefolded diaper are securely fastened together at each of the side edgesin an area closely adjacent the transverse fold in a manner to shorteneach of said side edges to prevent extension of the side edges to fulllength and to provide downwardly extendiNg fin portions adjacent thetransverse fold of each of said side edges, which fin portions areretained when the prefolded diaper is opened up and applied to aninfant.
 2. The prefolded diaper of claim 1 wherein said wing foldcomprises a triangular wing fold.
 3. The prefolded diaper of claim 1wherein said wing fold comprises a longitudinal wing fold.
 4. Theprefolded diaper of claim 1 wherein said side edges are shortened in anamount in the range of 8 percent to 14 percent of the original diaperlength.
 5. The prefolded diaper of claim 1 wherein the side edges ofsaid downwardly extending fins portions are sealed.